A grinding and rolling process suitable for high manganese non-magnetic steel

Abstract

The application discloses a kind of suitable for high manganese non-magnetic steel's regrinding rolling process, belong to technical field.The regrinding rolling process includes the following steps: (1) using the regrinding process of ladder transition, the upper surface edge defect of high manganese non-magnetic steel blank is regrinded treatment;(2) using the regrinding process of ladder transition symmetric with upper surface to the lower surface of blank regrinding treatment;(3) the blank after regrinding treatment of upper surface and lower surface is heated treatment;(4) using two-stage controlled rolling process.The regrinding rolling process used in the application is regrinded by ladder transition in the place where blank edge has defect, without regrinding the entire lower surface, after using this regrinding method, the regrinding amount of blank is reduced, and the regrinding efficiency is improved, and the blank yield is improved.The application uses economic TMCP process, and the process is simple, the production cycle is short, and the production cost is low.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of steel manufacturing, in particular to a grinding and rolling process suitable for high manganese non-magnetic steel. BACKGROUND

[0002] As a kind of functional steel material, non-magnetic steel is a low magnetic steel material that basically does not produce magnetic induction under the action of a magnetic field. Its relative magnetic permeability value is slightly greater than 1, and its magnetization in a magnetic field is very weak, which is called the so-called non-magnetic phenomenon, so it is called non-magnetic steel. Among them, high manganese non-magnetic steel has the advantages of high hardness, high wear resistance, high strength, low magnetic conductivity, etc., and thus becomes an important material in the fields of power, transportation and nuclear industry, which are related to people's livelihood and civilian use.

[0003] However, high manganese non-magnetic steel belongs to austenitic steel, and has a large thermal expansion coefficient. During the processing, the shell shrinks seriously when solidifying in the crystallizer, which easily leads to uneven shell thickness and causes defects such as surface depression and cracks of the blank.

[0004] Invention patent CN115383408 discloses a high manganese non-magnetic steel rolling process. The invention is characterized by using upper and lower surface grinding, combining the characteristics of non-magnetic steel, selecting appropriate cutting nozzles using flame cutting method, and timely cleaning the cutting nubs to prevent the cutting nubs from affecting the surface quality of the steel in the subsequent rolling process. The invention reasonably solves the cutting problem of non-magnetic steel. However, the invention still has the technical problems of low yield, many rolling process control points, and complex process. SUMMARY

[0005] The present application aims to provide a grinding and rolling process suitable for high manganese non-magnetic steel with high yield and simple process.

[0006] Technical solution: The grinding and rolling process suitable for high manganese non-magnetic steel according to the present application comprises the following steps:

[0007] (1) Using a stepped transition grinding process to grind the upper surface edge defects of the high manganese non-magnetic steel blank;

[0008] (2) Using a stepped transition grinding process symmetrical to the upper surface to grind the lower surface of the blank;

[0009] (3) Heating the blank after the upper surface and lower surface grinding treatment;

[0010] (4) Using a two-stage controlled rolling process.

[0011] Further, in step (1), the parameters of the grinding process of the step transition are: each step width is 240-260 mm, the height difference is 6-12 mm, and the transition angle is 25-30°, preferably, each step width is 250 mm, the height difference is 10 mm, and the transition angle is 25°.

[0012] Further, in step (1), the number of gradients of the step transition is 1-3, preferably, the number of gradients is 2.

[0013] Further, in step (1), the thickness of the blank is 200-300 mm.

[0014] Further, in step (3), the heating treatment condition is: the temperature is 1220±20℃, and the total furnace time is the thickness of the blank×(0.9-1.5) min / mm.

[0015] Further, in step (4), in the rolling process, when the thickness of the blank is ≥2.0×the thickness of the high-manganese non-magnetic steel, the finish rolling temperature is controlled at 800-880℃.

[0016] Further, the thickness of the high-manganese non-magnetic steel is 8-80 mm, preferably 20-60 mm; when the thickness of the high-manganese non-magnetic steel is 40-80 mm, the red temperature is ≤350℃.

[0017] Further, the high-manganese non-magnetic steel is 20Mn23ALV.

[0018] Beneficial effects: Compared with the prior art, the present application has the following remarkable advantages:

[0019] (1) The present application provides a grinding rolling process suitable for high-manganese non-magnetic steel 20Mn23ALV to solve the technical problems existing in the grinding rolling process of the prior art high-manganese non-magnetic steel. The high-manganese non-magnetic steel belongs to austenitic steel, and the thermal expansion coefficient is large. When solidified in the crystallizer, the blank shell shrinks seriously, which easily leads to uneven thickness of the blank shell, causing defects such as surface depression and cracks of the blank. The present application process includes grinding the defective parts of the blank edge, without grinding the entire lower surface. After using this grinding method, the blank grinding amount is reduced, the grinding efficiency is improved, and the blank yield is improved by 2%-5%.

[0020] (2) The high-manganese non-magnetic steel plate produced by the economic TMCP process of the present application has a specification of 8-80 mm, and a two-stage controlled rolling process is used to roll the steel plate, and then the thick plate ≥40 mm is cooled by water, which shortens the cooling time and does not need to be heat treated. The process is simpler, the production cycle is short, and the production cost is low. BRIEF DESCRIPTION OF DRAWINGS

[0021] Figure 1The size diagram of the blank after the grinding of the embodiment 1 of the present application is shown in Fig. 1.

[0022] Figure 2 The size diagram of the blank after the grinding of the comparative example 1 of the present application is shown in Fig. 2.

[0023] Figure 3 The size diagram of the blank after the grinding of the embodiment 2 of the present application is shown in Fig. 3.

[0024] Figure 4 The size diagram of the blank after the grinding of the comparative example 2 of the present application is shown in Fig. 4. DETAILED DESCRIPTION

[0025] The present application will be further described in conjunction with the specific embodiments and the accompanying drawings.

[0026] Embodiment 1: The grinding and rolling process of the 20*2000mm high manganese non-magnetic steel 20Mn23ALV, including the following steps:

[0027] 1) The edge defects on the upper surface of the blank are ground, and the edge is lower than the center after the grinding, and the step transition is adopted, and the width of each step is 250mm, the height difference is 10mm, and the transition angle is 25°;

[0028] 2) The lower surface of the blank is ground by using the symmetrical step transition mode of the upper surface, and the specific size of the blank after the grinding is shown in Fig. 2. Figure 1

[0029] 3) Heating process, the billet is heated by using a heating furnace, the heating section temperature is 1225℃, and the total furnace time is 286min;

[0030] 4) Two-stage controlled rolling is adopted, after the steel plate comes out of the heating furnace, two-stage controlled rolling is adopted, and the thickness of the warm blank is 30mm, and the final rolling temperature is 820℃.

[0031] The final steel plate has a rolling length of 20*2210*24900, and the steel plate yield is 83.4%.

[0032] Comparative example 1: The grinding and rolling process of the 20*2000mm high manganese non-magnetic steel 20Mn23ALV, including the following steps:

[0033] 1) The edge defects on the upper surface of the blank are ground, and the edge defects on the upper surface of the blank are ground, and the entire lower surface of the blank is ground, and the width of each step of the upper surface is 250mm, the height difference is 10mm, and the transition angle is 24°;

[0034] 2) The lower surface of the blank is ground, and the entire surface of the blank is ground, and the size after the grinding is shown in Fig. 2. Figure 2

[0035] ​​3) heating process, the billet is heated by a heating furnace, the heating section temperature is 1230℃, and the total in-furnace time is 288min;

[0036] 4) two-stage controlled rolling is adopted, after the steel plate is discharged from the heating furnace, two-stage controlled rolling is adopted, the thickness of the warm billet is 30mm, and the finish rolling final rolling temperature is 821℃.

[0037] The rolling length of the prepared steel plate is 20*2209*23889, and the yield rate is 81.2%.

[0038] Example 2: a grinding rolling process of 60*2000mm high-manganese non-magnetic steel 20Mn23ALV, comprising the following steps:

[0039] 1) the upper surface edge defects of the billet are ground, the edge is lower than the center after grinding, a stepped transition is adopted, the width of each step is about 250mm, the height difference is 10mm, and the transition angle is 25°;

[0040] 2) the lower surface of the billet is ground in a symmetrical stepped transition mode with the upper surface, and the size of the billet after grinding is as follows Figure 3

[0041] 3) heating process, the billet is heated by a heating furnace, the heating section temperature is 1233℃, and the total in-furnace time is 287min;

[0042] 4) two-stage controlled rolling is adopted, after the steel plate is discharged from the heating furnace, two-stage controlled rolling is adopted, the thickness of the warm billet is 121mm, and the finish rolling final rolling temperature is 875℃.

[0043] In the step 4), when the thickness of the rolled steel plate is greater than or equal to 40mm, the red temperature is 330℃.

[0044] The rolling length of the prepared steel plate is 60*2206*8655, and the yield rate is 80.3%.

[0045] Comparative Example 2: a grinding rolling process of 60*2000mm high-manganese non-magnetic steel 20Mn23ALV, comprising the following steps:

[0046] 1) the upper surface edge defects of the billet are ground, the edge is lower than the center after grinding, a stepped transition is adopted, the width of each step is about 250mm, the height difference is 10mm, and the transition angle is 25°;

[0047] 2) the lower surface of the billet is ground in a symmetrical stepped transition mode with the upper surface, and the size of the billet after grinding is as follows Figure 4

[0048] 3) heating process, the billet is heated by a heating furnace, the heating section temperature is 1233℃, and the total in-furnace time is 287min; ​​

[0049] 4) two-stage controlled rolling is adopted, after the steel plate is taken out from the heating furnace, two-stage controlled rolling is adopted, and the warm blank thickness is 121mm; the finish rolling temperature is 872℃;

[0050] When the thickness of the rolled steel plate in the step 4) is greater than 40mm, the re-red temperature is 331℃.

[0051] The rolling length of the prepared steel plate is 60*2206*8510, and the yield rate is 77.8%.

[0052] According to the above embodiment, it can be seen that the yield rate of the prepared high-manganese non-magnetic steel plate is high, the process is simple, the production cycle is short, the production cost is low, the application range is wide, and the market prospect is good.

Claims

1. A finishing rolling process suitable for high manganese non-magnetic steel, characterized in that, The method comprises the following steps: (1) using a step transition grinding process to grind the upper surface edge defects of the blank of high manganese non-magnetic steel; the parameters of the step transition grinding process are: the width of each step is 240-260 mm, the height difference is 6-12 mm, and the transition angle is 25-30°; the number of steps of the step transition is 1-3; the high manganese non-magnetic steel is 20Mn23ALV; (2) using a step transition grinding process symmetrical to the upper surface to grind the lower surface of the blank; (3) heating the blank after the upper surface and the lower surface are ground; (4) using a two-stage controlled rolling process.

2. The resharpening rolling process of claim 1, wherein, In step (1), the parameters of the step transition grinding process are: the width of each step is 250 mm, the height difference is 10 mm, and the transition angle is 25°.

3. The resharpening rolling process of claim 1 wherein, In step (1), the thickness of the blank is 200-300 mm.

4. The resharpening rolling process of claim 1 wherein, In step (3), the heating treatment conditions are: the temperature is 1220±20℃, and the total furnace time = the thickness of the blank × (0.9-1.5) min / mm.

5. The resharpening rolling process of claim 1 wherein, In step (4), when the thickness of the blank is ≥2.0×the thickness of the high manganese non-magnetic steel, the finish rolling final rolling temperature is controlled at 800-880℃ in the rolling process.

6. The resharpening rolling process of claim 1 wherein, The thickness of the high manganese non-magnetic steel is 8-80 mm.

7. The resharpening rolling process of claim 6, wherein, When the thickness of the high manganese non-magnetic steel is 40-80 mm, the red temperature is ≤350℃.

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